1 files changed, 24 insertions, 14 deletions

diff --git a/arch/tile/mm/pgtable.c b/arch/tile/mm/pgtable.c
index 87303693a072..2410aa899b3e 100644
--- a/arch/tile/mm/pgtable.c
+++ b/arch/tile/mm/pgtable.c
@@ -177,14 +177,10 @@ void shatter_huge_page(unsigned long addr)
         if (!pmd_huge_page(*pmd))
                 return;
 
-        /*
-         * Grab the pgd_lock, since we may need it to walk the pgd_list,
-         * and since we need some kind of lock here to avoid races.
-         */
-        spin_lock_irqsave(&pgd_lock, flags);
+        spin_lock_irqsave(&init_mm.page_table_lock, flags);
         if (!pmd_huge_page(*pmd)) {
                 /* Lost the race to convert the huge page. */
-                spin_unlock_irqrestore(&pgd_lock, flags);
+                spin_unlock_irqrestore(&init_mm.page_table_lock, flags);
                 return;
         }
 
@@ -194,6 +190,7 @@ void shatter_huge_page(unsigned long addr)
 
 #ifdef __PAGETABLE_PMD_FOLDED
         /* Walk every pgd on the system and update the pmd there. */
+        spin_lock(&pgd_lock);
         list_for_each(pos, &pgd_list) {
                 pmd_t *copy_pmd;
                 pgd = list_to_pgd(pos) + pgd_index(addr);
@@ -201,6 +198,7 @@ void shatter_huge_page(unsigned long addr)
                 copy_pmd = pmd_offset(pud, addr);
                 __set_pmd(copy_pmd, *pmd);
         }
+        spin_unlock(&pgd_lock);
 #endif
 
         /* Tell every cpu to notice the change. */
@@ -208,7 +206,7 @@ void shatter_huge_page(unsigned long addr)
                      cpu_possible_mask, NULL, 0);
 
         /* Hold the lock until the TLB flush is finished to avoid races. */
-        spin_unlock_irqrestore(&pgd_lock, flags);
+        spin_unlock_irqrestore(&init_mm.page_table_lock, flags);
 }
 
 /*
@@ -217,9 +215,13 @@ void shatter_huge_page(unsigned long addr)
  * against pageattr.c; it is the unique case in which a valid change
  * of kernel pagetables can't be lazily synchronized by vmalloc faults.
  * vmalloc faults work because attached pagetables are never freed.
- * The locking scheme was chosen on the basis of manfred's
- * recommendations and having no core impact whatsoever.
- * -- wli
+ *
+ * The lock is always taken with interrupts disabled, unlike on x86
+ * and other platforms, because we need to take the lock in
+ * shatter_huge_page(), which may be called from an interrupt context.
+ * We are not at risk from the tlbflush IPI deadlock that was seen on
+ * x86, since we use the flush_remote() API to have the hypervisor do
+ * the TLB flushes regardless of irq disabling.
  */
 DEFINE_SPINLOCK(pgd_lock);
 LIST_HEAD(pgd_list);
@@ -469,10 +471,18 @@ void __set_pte(pte_t *ptep, pte_t pte)
 
 void set_pte(pte_t *ptep, pte_t pte)
 {
-        struct page *page = pfn_to_page(pte_pfn(pte));
-
-        /* Update the home of a PTE if necessary */
-        pte = pte_set_home(pte, page_home(page));
+        if (pte_present(pte) &&
+            (!CHIP_HAS_MMIO() || hv_pte_get_mode(pte) != HV_PTE_MODE_MMIO)) {
+                /* The PTE actually references physical memory. */
+                unsigned long pfn = pte_pfn(pte);
+                if (pfn_valid(pfn)) {
+                        /* Update the home of the PTE from the struct page. */
+                        pte = pte_set_home(pte, page_home(pfn_to_page(pfn)));
+                } else if (hv_pte_get_mode(pte) == 0) {
+                        /* remap_pfn_range(), etc, must supply PTE mode. */
+                        panic("set_pte(): out-of-range PFN and mode 0\n");
+                }
+        }
 
         __set_pte(ptep, pte);
 }